Zero forcing equalization of multiuser time-varying nonlinear systems

Multiuser communication systems which experience intersymbol interference and nonlinearities can be modeled using the Volterra series. In this paper we consider the design of a linear multichannel zero forcing equalizer for a multiuser Volterra (nonlinear) system. Time-variations in the Volterra systems are modeled using basis expansions, and equivalent multiple-input time-invariant systems are derived. Equalizers are designed from the channel matrix and a training sequence, and complex exponential basis frequencies are estimated. Simulations demonstrate the effectiveness of the equalizer on a number of different systems.